In a motor-driven pneumatic striking mechanism, the striking piston is periodically accelerated in a guide tube by an air spring so that it strikes a tool at a front turning point. The principle of the air spring calls for an air-tight fit of the striking piston in the guide tube. It must not fail due to high mechanical loads from kickbacks or from thermo-mechanical stresses, i.e. if the striking mechanism heats up to temperatures in excess of 100° C. Furthermore, the striking piston has to move smoothly in the guide tube so that it does not suppress the relatively weak coupling of the motor drive via the air spring. Consequently, in order to safeguard the mechanical and thermo-mechanical properties, the guide tube is made out of a solid cylinder or out of a pipe having a small inner diameter by means of a metal-cutting procedure.